All the right noises

Young children learn words amazingly quickly. Even 6-month-old babies show signs of word recognition1, and by around two years old toddlers can work out what a new word means for themselves, without needing an adult to teach them2. So far, so brainy!

But although toddlers can establish what a word means when they’ve just heard it, this doesn’t mean they’ll remember that word later on – learning a new word takes many repetitions3. In fact, although it looks impressive, children’s ability to store and recall words is relatively fragile and affected by many different factors. In particular, noise in the learning environment has a bearing on word learning – and not necessarily the kind you hear!

For example, children find it easier to learn an object’s name when the learning environment contains visual noise, such as another object4, or several slightly different examples of the same object category5. However, not all noise is good for learning: children find it more difficult to learn words when there are lots of objects competing for their attention6 or, during shared reading, if they’re trying to learn a single word from lots of different books7.

So, the story so far is mixed. However, in order for us to support children’s language development it’s important for us to understand the different factors that help – or hinder – word learning. To find out more, we decided to examine low-level, background visual noise affected word learning. On the one hand, it might be distracting for children and make learning more difficult; on the other, it might help word learning, possibly by keeping children interested. Either way, we reasoned that exploring the effect of background noise on word learning would tell us something new about how we can help children to learn.

To this end, we taught two-and-a-half year old children a made-up word for new object by showing them pictures on a computer screen and playing them a recording of a woman speaking (for example Look! A tife! Wow, a tife! Where’s the tife?). Importantly, one group of children saw objects on the same, white background repeatedly, and the other group saw the same object on several uniform coloured backgrounds, for example green, blue and pink. Key to this study is that the second group of children experienced more visual noise during learning, but everything else children saw and heard was identical between groups.

After around 5 minutes of training we tested whether children had learned words by showing them pictures of the objects they had just seen and playing them the words they had just heard. Throughout this task we recorded where children were looking on the screen using an eyetracker, which allowed us to calculate whether children responded to the words by looking at the appropriate objects. The results we found were surprising! Children only learned words after seeing objects on different coloured backgrounds, which is unexpected given that the coloured backgrounds task is arguably more difficult or distracting than the same backgrounds task.

So what’s going on? We believe that the coloured backgrounds helped children’s generalisation, which is a crucial part of word learning. If a child learns that the fluffy, tabby, miaouwing animal at home is called cat, that knowledge isn’t very useful unless they can generalise cat to the small stuffed toy they play with at nursery, or to the black-and-white cartoon character that rides around in Postman Pat’s van (but of course, children also have to learn not to overgeneralize Jess to all cats!). In this study, when we tested children’s word learning we showed them grey backgrounds, which neither group had seen before. As a consequence, children in the white backgrounds group may have struggled to generalise what they’d learned to a new background, whereas children in the coloured backgrounds group had learned to generalize form the blue background to the green background to the pink background and so on during training.

What’s really exciting about this study is that it shows that adding visual noise – and therefore difficulty – to learning can actually help, pointing to ways of supporting children’s learning, such as through picture books, apps or games. It also raises the question of whether other types of noise like the stuff you can hear, or perhaps spatial location, could have a similar effect. These studies are currently underway, so watch this space! Overall, though, this work underlines the important and often overlooked point that learning language isn’t just about hearing language: what children see is vitally important too.

Acknowledgements

This work was supported by the ESRC International Centre for Language and Communicative Development (LuCiD; [ES/L008955/1]), and an ESRC Future Research Leaders Fellowship to Katie Twomey (ES/N01703X/1). Data for this study were collected as part of an MSc project carried out by Lizhi Ma in Lancaster University Babylab.

We are very grateful to all the parents and toddlers who took part in this study – we couldn’t do it without you!